Applying a new demographic framework to understand and project consequences of climate change in size- and age-structured populations

Figure. Overview of main elements in the IPM framework to be used in this project.

About the project

Freshwater ecosystems are particularly vulnerable to climate change, because of high pressure from other human activities and because freshwater species have limited possibilities to adjust by migration. Temperate Northern lakes have shown a warming trend over the last decades, and climate models predict a continued increase in average temperatures in the future.

In order to understand population level consequences of climate change as well as other impacts, we need to consider how individual responses depend on properties like body size or age. In aquatic organisms vital rates like survival and reproduction are often largely determined by body size. In this project we will extend and apply the demographic model framework of integral projection models (IPM) to study impacts of climate change and other factors (eutrophication, harvesting, stocking, extreme events) in two size-structured freshwater fish species: Pike (Esox lucius) from the lake Windermere (UK), and Brown trout (Salmo trutta) from the lake Mjøsa and river Gudbrandsdalslågen (Norway). As top predators, the responses of these species to climate change may have large consequences for the ecosystem.

Size structure is rarely considered in studies of population responses to climate change, but is likely important for many organisms. This project brings together recently developed theory and existing high quality data to help answer some of the unresolved questions of climate change research, providing valuable knowledge for size-structured management.